Photo-Catalytic Properties of Ceramic Coating of TiO2

Abstract:

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TiO2 coatings on ceramic substrate were prepared using TiOSO4 and silica sol. Coatings were
then heat-treated respectively at 300°C, 400°C or 500°C for 30mins. Degradation of the solution of
chlorinated methane by UV light and TiO2 coating were investigated. It can be concluded from the results
that the coating with composition of 80wt%TiO2-20wt%SiO2 heated at 500°C display better degradation
effect than the other coatings. As the initial concentration of chloromethane goes up, the degradation rate
increases; while as the degree of substitution by chlorine goes up, the catalytic effects decreases.

Abstract: A number of experiments were carried out with different Ce-Zr oxides doped
La3+、Pr3+ or Mn4+ in order to improve their performance as a promoter for three way
catalyst(TWC). The XRD results showed that the thermal stability of Ce-Zr oxide doped
lanthanum or praseodymium was improved, especially at high temperature. H2-TPR test
detected the low –temperature redox behavior of Ce-Zr oxide was promoted strongly
attributed to the MnO2, with calcined temperature increasing, the reduction peaks were
moved to high temperature for Ce-Zr oxide doped La3+ and Pr3+. The catalytic activity of
Ce-Zr oxide doped Mn4+ was also enhanced, the light-off temperature was lower 10K than
Ce-Zr oxide; the conversions of CO and THC were higher 3-4% than Ce-Zr oxide.

Abstract: The catalytic ozonation which treated nitrobenzene in extracted groundwater with high concentration was studied.The experiment showed that the optimization of catalysts was that the manganese nitrate and iron nitrate were dissolved to dip the activated alumina in 10 percent of mass concentration, the ratio of manganese to iron was 2:1, the calcination temperature was 450°C with six hours. The catalyst was characterized by SEM-EDS too; Adsorption of catalyst, air stripping, increasing concentration, temperature and pH all had effect on this reaction system. When pH was 9,temperature was 25 °C and catalyst dosage was 30g/L, the removal rate of nitrobenzene could reach 68.8%.

Abstract: A new catalyst of gold supported on nanometal oxide for oxidation of SO2 was developed. Deposition-precipitation method was used to prepare gold-based catalysts. The catalytic activity of the catalysts was evaluated by determining the concentration of SO2 with gas chromatography under reaction temperature from 100 to 700°C. The results showed that there was an enhancement of catalytic activity when gold nanoparticles were dispersed on the surface of nano-metal oxides, furthermore, γ-Fe2O3 showed the highest activity as the support of the colloidal gold supported catalysts among the nanometal oxides including γ-Fe2O3, Fe2O3, ZnO, and Al2O3. It was also found that water vapour in the reaction enhanced the catalytic activity of Au/γ-Fe2O3. The Au/γ-Fe2O3 was characterized by XRD and FTIR methods, which indicated that the gold nanoparticles were dispersed on the γ-Fe2O3 support and sulfate species were formed on the surface of catalysts.

Abstract: A series of rare earth perovskite-type oxides La09Sr0.1Co0.9Mn0.1O3La08Sr0.2Co0.8Mn0.2O3 and La05Sr0.5Co0.5Mn0.5O3 were prepared along the sol-gel method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy techniques (TEM) and catalytic activity measurement for combustion of CH4. The results indicated that a perfect crystal structure of perovskite was formed and La3+ and Co3+ ions were partly replaced by Sr2+ and Mn3+ ions, respectively, and perovskite-type oxides were composed of nanocrystals with particle size of 20~50nm. The catalytic activity for the combustion of CH4 was evaluated and La05Sr0.5Co0.5Mn0.5O3 exhibited best performance with the temperature of 50% and 90% conversion efficiency of 723K and 833K.

Abstract: TiO2, 50%TiO2-ZrO2 and 80%TiO2-ZrO2 were prepared by sol-gel method. The manganese oxides were impregnated on the carrier and the catalysts were used for low-temperature selective catalytic reduction of NOx with ammonia (NH3-SCR) in the presence of excess O2. The samples were characterized by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The results showed that the particle size of 80%TiO2-ZrO2 is the smallest among the three kind of carrier and the particles are highly dispersed. By adding the ZrO2, the Zr4+ ions replaced the lattice Ti4+ ions, and thus caused lattice distortion in the TiO2 and an increase of the active point amount on the carrier. Furthermore, the Zr also promoted the dispersion of the active ingredients carried on the carrier, increased the surface concentration of Mn. The most active catalyst was obtained with a mass MnOx/80%TiO2-ZrO2 ratio of 0.1.The best MnOx/80%TiO2-ZrO2 catalyst yielded nearly 92.6% NO conversion at 130°C at a high space velocity of 67,000 h-1.